<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>属性</title>
</head>
<body>
    <div class="cls">第一个</div>
    <div class="cls">第二个</div>
    <div id="d1">第三个</div>
    <div id="d2">第四个</div>
    <div style="background-color: aquamarine">第五个</div>
</body>
</html>